From 37566c51d0e80fbf3837b6527c501727521e92cd Mon Sep 17 00:00:00 2001
From: XANTRONIX Development
Date: Wed, 2 Feb 2022 00:12:09 -0500
Subject: nailed it

---
 src/audio.c | 78 ++++++++++++++++++++++++++++++++++++++-----------------------
 1 file changed, 49 insertions(+), 29 deletions(-)

diff --git a/src/audio.c b/src/audio.c
index 8853164..10f7a34 100644
--- a/src/audio.c
+++ b/src/audio.c
@@ -106,50 +106,70 @@ static inline void *ptr(xas_audio_stream *stream, void *buf, size_t index) {
 ssize_t xas_audio_stream_write(xas_audio_stream *stream,
                                  void *samples,
                                  size_t count) {
-    size_t left  = count,
-           index = 0;
+    size_t index_i = 0;
 
-    if (stream->buffer_count > 0) {
-        size_t remainder = stream->buffer_size - stream->buffer_count;
+    if (stream->buffer_count + count > stream->buffer_size) {
+        /*
+         * If the number of samples offered, plus the number of items currently
+         * in the buffer exceeds the buffer size, fill the buffer to capacity
+         * and flush it.
+         */
+        size_t remaining = stream->buffer_size - stream->buffer_count;
 
         memcpy(ptr(stream, stream + 1, stream->buffer_count),
-               ptr(stream, samples, 0),
-               stream->sample_size * stream->channels * remainder);
+               ptr(stream, samples,    index_i),
+               remaining * stream->sample_size * stream->channels);
 
-        stream->buffer_count += remainder;
-
-        if (stream_flush(stream) < 0) {
-            goto error_stream_flush;
-        }
-
-        left  -= remainder;
-        index += remainder;
-    }
-
-    while (left > stream->buffer_size) {
         if (stream->drain(stream->ctx,
-                          ptr(stream, samples, index),
+                          ptr(stream, stream + 1, 0),
                           stream->buffer_size,
                           stream) < 0) {
             goto error_stream_drain;
         }
 
-        left  -= stream->buffer_size;
-        index += stream->buffer_size;
-    }
+        index_i += remaining;
 
-    memcpy(ptr(stream, stream + 1, 0),
-           ptr(stream, samples, index),
-           stream->sample_size * stream->channels * left);
-
-    stream->buffer_count = left;
+        stream->buffer_count = 0;
+    }
 
-    index += left;
+    /*
+     * While there are still samples to buffer or flush...
+     */
+    while (index_i < count) {
+        size_t remaining = count - index_i;
+
+        if (remaining >= stream->buffer_size) {
+            /*
+             * If the number of samples remaining is greater than the target
+             * buffer size, then drain directly from the source buffer to the
+             * output an amount equal to the buffer size.
+             */
+            if (stream->drain(stream->ctx,
+                              ptr(stream, samples, index_i),
+                              stream->buffer_size,
+                              stream) < 0) {
+                goto error_stream_drain;
+            }
+
+            index_i += stream->buffer_size;
+        } else {
+            /*
+             * Enough of the input has been drained that it can be copied to
+             * the target buffer.
+             */
+            memcpy(ptr(stream, stream + 1, stream->buffer_count),
+                   ptr(stream, samples,    index_i),
+                   remaining * stream->sample_size * stream->channels);
+
+            index_i += remaining;
+
+            stream->buffer_count += remaining;
+        }
+    }
 
-    return index;
+    return 0;
 
 error_stream_drain:
-error_stream_flush:
     return -1;
 }
 
-- 
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